How to Fix Invalid MMI Code Problems

MMI code is the code which we enter in the phone that contains characters between * and #. The invalid MMI code error is a prominent problem which occurs due to a weak or no mobile network connection. It has been observed that due to this problem, many people cannot make or receive calls or even can’t send a text message.

One of the very prominent problem that we come across is Connection Problem or Invalid MMI Code. This message may also say that there has been an error is entering the MMI code. Otherwise, an attempt is being made through a phone having two active connections. So, it is recommended to disable the other sim and use the actual sim in which you are attempting to check your account balance, topping up or performing any function designed by your service provider.

Now, discussing about the major causes of the invalid MMI code problem. In different countries, cell phone service providers define the same USSD string to execute the same task. But it you are getting “Connection problem or invalid MMI code”, this error mainly occurs because of the connection issues & sim card authorization. This issue mostly happen in dual sim smartphones.

How to fix Connection Problems or Invalid MMI Codes


This is the simplest and the most effective way on which very less people pay attention to.

App Disabling- 

there are a lot of people who think that deleting the app may remove the MMI Code error. But how will you identify which app is causing issues. For knowing this first open the smartphone in safe mode.

Safe mode of  mobile phone is almost similar to  safe mode of computer which temporarily disable all the built-in as well as the downloaded apps on your phone.

Now, in order to find the culprit app interfering the network operations, we need to follow the following steps:

  • Switch Off your phone
  • Hold the power button
  • While holding the power button, keep tapping the menu/home button
  • Now, when you see the greetings with a safe mode logo
  • Enter the USSD string you were trying to enter within the dialer and see if it is working or not
  • If it is working, then certainly there is an app which is causing the Invalid MMI Code error on your phone.
  • Restart your phone and remove the recently installed apps.


This is another simple and effective way to fix the error on the android phone. This can be done by just adding a comma at the end of the prefix code.

For example, if your prefix code is *123*1#, then you just need to add a comma at the end of the string.  Like, *123*1#, will solve the problem.


To fix this problem of Invalid MMI code in Samsung Galaxy, just make your device enter into the information mode and activate “Radio and Turn on IMS over SMS”

To enter into the information mode:

  • Dial *#*#4636#*#* from your mobile phone
  • Navigate to Device Information
  • Click “Run Ping Test”
  • Click  “Turn off Radio”
  • Click  “Turn on IMS over SMS”
  • Finally restart the phone


Restarting your mobile  phone many times sometimes can do the magic. Basically, turn ON your phone and navigate to network settings. Then hold the power and the home button together until your phone turns off. Then again switch it on to get rid of this problem. May be this simple exercise helps you out.


Another easy method to get rid off the problem is just follow the below steps :

Go to –

  • Settings in your mobile device
  • Then choose Network Connections
  • In network connection navigate to Mobile Networks
  • It will refelect available networks
  • Choose the service provider of your network
  • If even after choosing your  selected network and you still get Invalid MMI Code problem then  Connect again and repeat the above steps  4-5 times.
  • Problem will get solved


This Post Has 4 Comments

  1. alistair

    I just bought a unlocked art phone and the used calls out like a phone call instead of giving me my credit balance. How can I fix this?

  2. Lingelihle

    please help me with Mmi code please’ please

  3. veronica Turpin

    I don’t have a comma on my dial pad. I also tried using a + but that didn’t work either.
    I have Samsung galaxy s7



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